TABLE 1.

Nucleophilic rate constant values for the reaction between ClDNB with biothiol series in aqueous media and phosphate solution at 25°C and 37°C.

Biothiol compound	$p{K}_a$	ClDNB aqueous media		ClDNB buffer phosphate
		$k_N$ (sM)−1 25°C	$k_N$ (sM)−1 37°C	$k_N$ (sM)−1 25°C	$k_N$ (sM)−1 37°C
L-Cysteine ethyl ester	6.50	0.10 ± 3 × 10−3	0.18 ± 6 × 10−3	0.13 ± 5 × 10−3	0.23 ± 0.01
Cysteine	8.10	0.12 ± 6 × 10−3	0.72 ± 0.02	0.15 ± 0.01	0.41 ± 0.02
DL-Homocysteine	8.25	0.25 ± 8 × 10−3	0.48 ± 0.01	0.57 ± 0.01	1.75 ± 0.04
Glutathione	8.75	1.26 ± 0.05	2.16 ± 0.07	1.74 ± 0.04	3.35 ± 0.10
N-Acetylcysteine	9.50	1.88 ± 0.08	3.80 ± 0.13	2.12 ± 0.05	5.14 ± 0.14